Eli linqaku lokuqala kuchungechunge amabini. Eli nqaku liza kuqala lixoxa ngembali kunye nemiceli mngeni yeIqondo elisekwe kwi-ThermistorIinkqubo zokulinganisa, kunye nokuthelekisa kwabo nge-thermometer (i-RTD) yokulinganisa yobushushu. Iya kuchaza nokukhetha i-thermistor, i-proser-spres, kunye nokubaluleka kwe-Sigma-Delta-Delta-to-debital-to-debital-to-debital-to-to-debital-to-Dedital-to-Dedital (ADCs) kule ndawo yesicelo. Inqaku lesibini liya kucacisa indlela eyandisa ngayo inkqubo yokulinganisa esekwe kwi-intermistor.
Njengoko kuchaziwe kwinqaku elidlulileyo, ukuxhasa i-RTD Sysor Sysor Syssor System, i-RTD ngumthi wokuhlangula ohluka kakhulu kubushushu. Abathengi basebenza ngendlela efanayo kwi-RTDS. Ngokungafaniyo ne-RTDS, enamaqondo obushushu amnandi, i-thermistotor inokuba neqondo lobushushu okanye elingalunganga. Iqondo lobushushu elingalunganga (i-NTC) inciphisa ukumelana nokunyuka kweqondo lobushushu, ngelixa iqondo lokuhlala lisebenza kakuhle (PTC) liyanda ngakumbi njengoko inyukele iqondo labo njengoko inyuka iqondo labo. Kwi-Fig. 1 Ibonisa iimpawu zempendulo ze-NTC eziqhelekileyo ze-NTC kunye ne-PTC TRMATORS kwaye zithelekise kwi-RTD curves.
Ngokuphathelele kwinqanaba lobushushu, ijika laseRTD iphantse igubungele i-thermister ebanzi kakhulu kunee-thermistors (okwesiqhelo -200 ° C) ngenxa yomda we-thermistor. I-RTDS idla ngokunikezelwa kwi-curves ebonakalayo emiselweyo, ngelixa i-curmistor ijika iguquka ngomenzi. Siza kuthetha ngale nkcukacha kwicandelo lokukhetha le-inqaku.
I-thermistors zenziwa kwizinto ezihlanganisiweyo, i-ceramics, i-polymers, okanye i-semicontueds (i-oxis yentsimbi) kunye neentsimbi ezimsulwa (iPlatinam, i-nickel, okanye ubhedu). Abaguquleli banokuthi babone amaqondo obushushu atshintsha ngokukhawuleza kune-દRDS, abonelela ngengxelo ngokukhawuleza. Ke ngoko, abaThengisi basetyenziswa rhoqo ngabasebenza kwizicelo ezifuna iindleko eziphantsi, ubungakanani obukhawulezileyo, iimvakalelo zamaqondo obushushu, kunye neelebhu zesakhiwo, okanye iilebhu zenzululwazi, okanye iilebhu zenkqubo. iinjongo. Izicelo.
Kwiimeko ezininzi, abathengisi be-NTC basetyenziselwa ukulinganiselwa kobushushu obuchanekileyo, hayi ii-ptc thermirs. Abanye abathengisi be-PTC bayafumaneka enokusetyenziswa kwisebuthelo zoKhuselo ngokugqithileyo okanye njenge-fuse ephindwe kabini kwizicelo zokhuseleko. Ukuchasana kweqondo lobushushu le-PTC libonisa i-PTC ye-PTC ibonisa indawo encinci ye-NTC ngaphambi kokuba ifike kwindawo yokuguqula (okanye i-curie), ngaphezulu kokuba inyukele i-ridius. Ngaphantsi kweemeko ezikhulu kakhulu, i-PTC ye-PTC iya kuvelisa ukuzifudulaza okuqinileyo xa ubushushu obugqithisileyo bungaphezulu, kwaye ukuxhathisa i-swing kugqithisa, kuya kuthintela igalelo langoku, ngaloo ndlela bathintela ukonakala. Indawo yokutshintsha ye-PTC ye-PTC iphakathi kwe-60 ° C kwaye i-120 ° C kwaye ayifanelekanga ekulawuleni imilinganiselo yobushushu kuluhlu olubanzi lwezicelo. Eli nqaku ligxile kwi-NTC Thermirs, enokuthi ilingane okanye ijonge amaqondo obushushu asusela kwi--80 ° C ukuya kwi-150 ° C. I-thermistors ye-NTC inamanqanaba okumelana nokususela kwi-OHMS embalwa ukuya kwi-10 mω nge-25 ° C. Njengoko kubonisiwe kwi-Fig. 1, Utshintsho ekuchanyoni ngenqanaba lesidumbu se-Celsius kubathengi babhengezwa ngakumbi kunokuba kunjalo. Xa kuthelekiswa nabathengisi, ubuntu obuphezulu be-thermistor kunye nexabiso lokuphiliswa kwe-therrmistor kunye nexabiso lokwenza lula igalelo legalelo, kuba abagcini bemiphumo engafuni naluphi na ugcino olukhethekileyo lwe-wiriss, olunje nge-3-wire, ukubuyekeza ukumelana nokunganyangeki. Uyilo lwe-thermistor lusebenzisa kuphela ubumbeko lwe-2-wire.
Ukulinganiswa kobushushu obungoyena mgangatho wobushushu obuphakathi kufuna ukulungiswa kwesiginali, i-analog-in-didital, ulayini, kunye nembuyekezo, njengoko kubonisiwe kwi-Fig. 2.
Nangona i-chain yomqondiso inokubonakala ilula, kukho izinto ezinzima ezichaphazela ubukhulu, iindleko, kunye nokusebenza kwebhodi yamamama. Iphothifoliyo ye-ADI ichanekile ipotifoliyo, enjenge-Add7124-4 / i-AD7124-8, enika inani lezibonelelo zoyilo lwenkqubo ye-thermal njengoko uninzi lweebhloko zokwakha ezifunekayo kwisicelo sakhelwe isicelo. Nangona kunjalo, kukho imiceli mngeni eyahlukeneyo ekufumaneni nasekuphumezeni isisombululo semilinganiselo yobushushu be-thermistor esekwe kwi-Thermistor.
Eli nqaku lixoxa ngemicimbi kwaye libonelela ngeengcebiso zokuzicombulula kwaye ezinye zenza lula inkqubo yoyilo yeenkqubo ezinjalo.
Kukho iintlobo ezahlukeneyo zeI-thermistors ye-NTCKwimarike namhlanje, ke ukukhetha i-thermistor efanelekileyo yesicelo sakho kunokuba ngumsebenzi otyhafisayo. Qaphela ukuba oomameli badweliswe ngokwexabiso labo, oluyindawo yabo yokumelana kwabo nge-25 ° C. Ke ngoko, i-10 kω ye-10 kω inothintelo oluthile lwe-10 kω nge-25 ° C. Abaguquleli banemilinganiselo yokuthintela okanye abasiseko isusela kwi-OHMS embalwa ukuya kwi-10 mω. I-Therrristors enereyithi yokuchasana ne-10 kω okanye ngaphantsi) ixhasa amaqondo obushushu asezantsi, anje nge-2000 ° 2 ° C ukuya kwi-70 c. Abaguquleli bereyithingi ephakanyisiweyo banokumelana namaqondo obushushu ukuya kuthi ga kwi-300 ° C.
Inqaku le-thermistor lenziwe nge-oxide yentsimbi. Abaguquleli bayafumaneka ngebhola, imilo ye-radial kunye ne-smd. I-TheRMISTOR OKANYE I-EPOXY YAYIPHILA NOKHUSELEKILEYO OKANYE IGRISTE YOKUKHUSELEKILEYO YOKUKHUSELEKILEYO. I-EOPOXY ye-EUPOXY I-TRERISTORS TRISTERS, i-radial kunye ne-radial kunye nendawo engaphezulu ilungele amaqondo obushushu ukuya kuthi ga kwi-150 ° C.. Abathengisi be-Bed Glad balungele ukulinganisa amaqondo obushushu aphezulu. Zonke iintlobo zengubo / zokupakisha zikwakhusela ngokuchasene nokungabikho. Abanye abathengi baya kuba nezindlu ezongeziweyo zokhuseleko olongezelelekileyo kwiindawo ezinobunzima. I-Bermistors Bedristors inexesha lokuphendula ngokukhawuleza kune-radial / smd. Nangona kunjalo, azihlali. Ke ngoko, uhlobo lomthendeleko osetyenzisiweyo luxhomekeke kwisicelo sokuphela kunye nokusingqongileyo apho i-thermistot ifumaneka khona. Uzinzo lwexesha elide lomthendeleko luxhomekeke kwinto ethile, ukupakisha kunye noyilo. Umzekelo, i-eporism-engqungquthela ye-Epoxy inokutshintsha i-0.2 ° C ngonyaka, ngelixa i-thermistor evaliweyo itshintsha kuphela i-0.02 ° C ngonyaka.
Abaguquleli beza ngokuchaneka okwahlukileyo. Abathengisi abaqhelekileyo bahlala bechanekile kwi-0.5 ° C ukuya kwi-1.5 ° C. Ixabiso lokunganyangeki kwe-thermistor kunye nexabiso le-BETA (umyinge we-25 ° C ukuya kwi-50 ° C / 85 ° C) abe nonyamezelo. Qaphela ukuba ixabiso le-beta lomthendeleko iyahluka ngokusebenza ngomenzi. Umzekelo, abathengisi be-10 kč nω bevela kubavelisi abahlukeneyo baya kuba namaxabiso ahlukeneyo e-beta. Ngeenkqubo ezichanekileyo ezichanekileyo, abathengisi abafana ne-Omega ™ 44kxx ingqina inokusetyenziswa. Banokuchaneka kwe-0.1 ° C okanye i-0,2 ° C ngaphezulu kwenqanaba lobushushu le-0 ° C ukuya kwi-70 ° C. Ke ngoko, uluhlu lwamaqondo obushushu anokulinganiswa kwaye ukuchaneka kwenziwe ngaphezulu kolo luhlu lwamaqondo athe ngqo nokuba abathengi balungele esi sicelo. Nceda uqaphele ukuba ukuphakama kokuchaneka kwe-Omega 4sxxx ingcelele, ukuphakama kwexabiso.
Ukuguqula ukunganyangeki kwi-degrees Celsius, ixabiso le-Beta lihlala lisetyenziswa. Ixabiso le-Beta limiselwa ngokwazi amanqaku amaqondo obushushu amabini kunye nokuxhathisa okungahambelaniyo kwinqanaba ngalinye lobushushu.
RT1 = Ukuxhathisa ubushushu 1 rt2 = Ukuchasana kobushushu 2 T1 = ubushushu 1 (k) t2 = ubushushu 2 (k)
Umsebenzisi usebenzisa ixabiso le-beta elikufutshane kuluhlu lobushushu olusetyenziswa kule projekthi. Uninzi lweedatha ze-irmistor lube uluhlu lwexabiso le-beta kunye nokunyamezelana nge-25 ° C kunye nokunyamezelwa kwexabiso le-beta.
Abaguquleli abaphezulu ngokuchanekileyo kunye nezisombululo eziphezulu zokuphelisa ngokuchanekileyo njenge-Omega ye-Omega ye-4xxx Sebenzisa i-Steinhart-Hart ukuguqula ukunganyangeki kwi-quelsius. I-Equation 2 ifuna ezi ntshukumo ezintathu a, b, kunye ne-C, iphinde inikezwe ngumvelisi wenzwa. Kuba i-qualing ye-equation iveliswa kusetyenziswa amanqaku amaqondo amaqondo amanebushushu, ukulingana okuphawuleka kunciphisa impazamo engeniswe ngokuhambelana (ngokwesiqhelo i-0.02 ° C).
A, B kunye no-C ziziints ezifumaneka kwiindlela ezintathu zokushishina. R = Ukuchasana kwe-thermistor kwi-OHMS T = Iqondo lokushisa kwi-K Degrees
Kwi-Fig. I-3 ibonisa uchulumaniso lwangoku lwenzwane yenzwa. Ukuqhuba okwangoku kusetyenziswa kwi-thermistor kwaye okufanayo kusetyenziswa kumvuzo ochanekileyo; Isicelo sokuchaneka sisetyenziswa njengokubhekiswa kumlinganiso. Ixabiso lokurhoxisa ireferensi kufuneka libe likhulu okanye lilingane nexabiso eliphezulu lokunganyangeki kwe-thermistor (kuxhomekeke kubushushu obuphantsi obulinganiswe kwinkqubo).
Xa ukhetha uchulumanco okwangoku, ukuxhathisa okuphezulu kwe-thermistor kufuneka kuthathelwe ingqalelo kwakhona. Oku kuqinisekisa ukuba i-voltage iphela inzwa kunye nesalathiso sokurhoxisa ihlala kwinqanaba elamkelekile kwi-elektroniki. Intsimi yoMthombo wangoku ifuna i-heram okanye i-oxtives ehambelana nayo. Ukuba i-thermistor inomsindo ophezulu kwiqondo lokulinganisa elilinganayo elilinganayo, oku kuya kukhokelela kwi-drive esezantsi kakhulu. Ke ngoko, i-voltage eveliswe ngaphaya kommeli kwiqondo lobushushu lincinci. Amanqanaba enzala esebenzayo angasetyenziselwa ukwenza umlinganiso wala magama aphantsi. Nangona kunjalo, inzuzo kufuneka icwangciswe ngokwahlula-hlula kuba inqanaba lesiginali ukusuka kumthendeleko wahluka kakhulu kubushushu.
Olunye ukhetho kukuseta inzuzo kodwa sebenzisa i-dynamic dynamic dyname okwangoku. Ke ngoko, njengoko inqanaba lesiginali ukusuka kwi-TherMISTORT, i-drive drive yangoku itshintsha ngokulinganayo ukuze i-voltage iphuhliswe kuyo yonke i-thermistor iphakathi koluhlu lwe-elektroniki. Umsebenzisi kufuneka aqinisekise ukuba i-voltage iphuhliswe kuyo yonke indawo yokurhoxiswa kwereferensi ikwinqanaba elamkelekileyo kwi-elektroniki. Zombini iinketho zifuna inqanaba eliphezulu lolawulo, ukubeka iliso rhoqo kwi-voltage kumthendeleko we-thermistor ukuze i-elektroniki inokulinganisa umqondiso. Ngaba ikhona indlela elula? Cinga ngovuyo lwamavoto.
Xa i-DC Voltage isetyenziswa kwi-thermistor, okwangoku ngokuzenzekelayo i-thermistor izikali ngokuzenzekelayo njengenguqulelo yokuxhathisa i-therrmtor. Ngoku, usebenzisa umkhuseli ochanekileyo endaweni yokurhoxisa, injongo yayo kukubala ukugela okwangoku ngumthendeleko, ngaloo ndlela kuvumela ukunganyangwa i-thermistor ukubalwa. Kuba i-voltage ye-drive ikwasetyenziswa njengesalathiso se-ADC, akukho nqanaba lokufumana inzuzo liyafuneka. Iprosesa ayinawo umsebenzi wokujonga i-gormistor golt, ukumisela ukuba inqanaba lesiginali lingalinganiswa yi-elektroniki, kwaye ukubala ukuba loluphi ixabiso lokufumana / ixabiso langoku kufuneka luhlengahlengiswe. Le yindlela esetyenziswe kweli nqaku.
Ukuba i-thermistotor inomgangatho omncinci wokuchasana nokuchasana nokuxhathisa, i-voltage okanye imfesane yangoku. Kule meko, ukuqhuba okwangoku kunye nokufumana inzuzo kunokulungiswa. Ke, isekethe iya kuba njengoko iboniswe kumzobo 3. Le ndlela ilungele ukulawula i-sensor kunye nokurhoxisa, okuxabisekileyo kwizicelo zombane eziphantsi. Ukongeza, ukuzifudumeza komthendeleko kuncitshiswa.
I-Voltagety inokusetyenziselwa i-theristors enereyithingi yokuchasana ephantsi. Nangona kunjalo, umsebenzisi kufuneka asoloko eqinisekisa ukuba okwangoku nge-sensor ayiphezulu kakhulu kwi-sensor okanye isicelo.
I-Voltimetion Frisege yenza lula ukuphunyezwa xa usebenzisa i-thermistor enenqanaba elikhulu lokuchasana kunye nodidi lobushushu olubanzi. Ukuxhathisa okukhulu kokuchasana kubonelela ngenqanaba elamkelekileyo lexesha. Nangona kunjalo, abaqulunqileyo kufuneka baqinisekise ukuba okwangoku kukho inqanaba elamkelekileyo kulo lonke udidi lobushushu oluxhaswe sisicelo.
I-Sigma-Delc ADCS inika izibonelelo ezininzi xa uyila inkqubo ye-Thermistorment. Okokuqala, kuba i-sigma-delta adc iphindaphindwe igalelo le-analog, ukugcwala kwangaphandle kugcinwa ubuncinci kwaye kuphela imfuneko yifiltha ye-RC. Banikezela bhetyebhetye kuhlobo lwe-filter kunye nenqanaba le-baud. Ukucoceka okwakhelwe-ngaphakathi kunokusetyenziselwa ukucinezela naluphi na uphazamiseko kwizixhobo ezixhonyiweyo. Izixhobo ezingama-24-bit ezinje nge-Add7124-4 / AD7124-8 zinesigqibo esipheleleyo ukuya kuthi ga kwi-21.7 bits, ngoko babonelela ngesisombululo esiphezulu.
Ukusetyenziswa kwe-sigma-delta adc ngokufanelekileyo ukwenze lula uyilo lwe-thermistor ngelixa kuncitshiswa ukucaciswa, iindleko zenkqubo, indawo yebhodi, kunye nexesha lokuthengisa.
Eli nqaku lisebenzisa i-Add7124-4 / i-AD7124-8 njenge-ADC kuba zinengxolo enkulu, i-ADC ephantsi, ichanekile kwi-PGA eyakhiwe-ye-PGA, i-ares, igalelo, kunye nesalathiso se-Buffer.
Nokuba usebenzisa i-voltage yangoku okanye i-drives, ukucwangciswa kwe-rabytometric kuyacetyiswa apho i-voltage yerejista kunye ne-insor voltage ivela kumthombo ofanayo wokuqhuba. Oku kuthetha ukuba naluphi na utshintsho olwenziweyo lomthombo ongoyiki aluyi kuchaphazela ukuchaneka komlinganiso.
Kwi-Fig. I-5 ibonisa i-drivest drived yangoku kwi-thermistotor kunye nokuchasa i-RREF, i-voltage iphuhliswe kuyo yonke i-RREF yi-voltage yerejista yokulinganisa i-thermistor.
Intsimi yangoku ayidingi ukuba ichaneke kwaye ingazinza njengezinzileyo njengazo naziphi na iimpazamo ezisentsimini ziya kupheliswa kolu hlengahlengiso. Ngokubanzi, imfazwe yangoku ithathelwa ingqalelo kwi-voltagety ye-voltage ngenxa yolawulo lomoya ophezulu lobuntununtunu kunye nogonyo lwengxolo enkulu xa i-sensor ikwindawo ekude. Olu hlobo lwendlela ye-bias luqhele isetyenziselwa i-RTDS okanye i-thermistors ngeenqobo zokuxhathisa eziphantsi. Nangona kunjalo, ngenxa ye-thermistotor enexabiso eliphezulu lokuxhathisa kunye nemvakalelo ephezulu, inqanaba lesiginali eveliswe ngutshintsho lwamaqondo obushushu liya kuba nkulu, ke kuya kusetyenziswa i-voltagecy. Umzekelo, i-10 Kωrmistor ye-10 kω ichasa i-10 kω nge-25 ° C. Nge-2,50 ° C, ukuxhathisa komthendeleko we-NTC ngu-441.17 kω. Ubuncinci be-drive yangoku i-50 μA inikezwe yi-AD7124-4 / i-AD7124-8 ivelisa i-441 ω × × × μ μ Abaguquleli badla ngokunxulumana okanye babekwe kufutshane ne-elektroniki, ngenxa yoko, ke ngokogona lokuqhuba okwangoku akunyanzelekanga.
Ukongeza i-resistor yemvakalelo ngothotho njengesekethe ye-Voltage Globacy iya kuthi ikhawulele i-thermistor kwixabiso layo elingaphantsi lokuchasana. Kolu lungiselelo, ixabiso lendlela yokuthintela imbono kufuneka ilingane nexabiso lokunganyangeki kwe-25 ° CC nge-10 kω nge-10 kω nge-10 kω nge-25 kω nge-25 kω isetyenzisiwe, i-RERONT kufuneka ibe yi-10 kω. Njengoko ubushushu obuguqukayo, ukuxhathisa kwe-thermismtor ye-NTC kuyatshintsha, kwaye umyinge we-voltage ye-Dristor nayo iyatshintsha, imphumo kwi-voltage yemveliso ihambelana nokuchasana nommeli we-NTC.
Ukuba ireferensi ye-voltage ekhethiweyo esetyenziselwa ukulawula i-thermistor kunye / okanye ngemisitho ehambelana ne-ADC Repreremere Voltage esetyenziselwa umlinganiso (inkqubo isetwe kumlinganiso we-voltage onxulumene noko (umzobo 7) uya kususa.
Qaphela ukuba i-testristor yengqondo (i-voltage iqhutywa) okanye ireferensi yokurhoxa (i-discaren) kufuneka inyamezele i-terali yokuqala kwaye yothoseleko olusezantsi, njengoko zombini izinto zinokuchaphazela ukuchaneka kwayo yonke inkqubo.
Xa usebenzisa i-thermistors ezininzi, i-voltage enye yobuqili inokusetyenziswa. Nangona kunjalo, i-thermistotor nganye kufuneka ibe nomvuzo wayo ofanelekileyo, njengoko kubonisiwe kwi-Fig. 8. Olunye ukhetho kukusebenzisa i-CounterX ye-Auntier yangaphandle okanye i-switch engachanekanga kwi-State, evumela ukwabelana ngokuthintela okuchanekileyo. Ngolu uqwalaselo, i-thermistor nganye ifuna ixesha lokuhlala xa ilinganiswa.
Isishwankathelo, xa siyilo lwenkqubo yokulinganisa yobushushu be-thermistor, kukho imibuzo emininzi ekufuneka iqwalaselwe: Ukukhetha i-sensor wiring, i-Sensor Wiring, Ukhetho lweNqaku, kunye nendlela eziguquguqukayo ze-ADC, kunye nendlela ezichaphazela ngayo ukuchaneka kwenkqubo. Inqaku elilandelayo kolu ngcelele licacisa indlela yokwandisa uyilo lwenkqubo kunye nohlahlo-lwabiwo mali lwendlela yenkqubo yendlela yokufezekisa ukusebenza kwakho.
IXESHA LOKUQALA: UPE-30 ukuya kwi-2022